Linear polymers of di(isopropenyl)benzene (DIPB) are highly unsaturated and may be used as addition fragmentation chain transfer agents in processes of making polymers by free radical polymerization or as reactive, unsaturated backbones for the further elaboration to functional oligomers or polymers. During free radical polymerization reactions, chain transfer agents may be added to propagating radicals and undergo fragmentation to create new radical forms. Molecules such as α-methylstyrene dimer (AMSD), unlike some other chain transfer agents, are easy to handle and generally do not cause discoloration or influence the stability of polymers. However, AMSD has some volatility, particularly when subjected to high temperature curing processes. A polymeric form of AMSD would be more suitable for some applications.
Linear polymers of di(isopropenyl)benzene (DIPB) are highly unsaturated affording multiple sites of reactivity when employed as base polymers for further functionalization. Functionalization reactions include reactions such as hydrocyanation yielding polynitriles, amination yielding polyamines or hydration yielding polyols. Furthermore, the polymers can be self-crosslinked or crosslinked with other materials by cationic reactions
One known method of making polymers of di(isopropenyl)benzene is by the anionic method as disclosed by Lutz et. al. (Makromolekulare Chemie, 183(11), 2787-97 (1982)), which is suitable for forming relatively small quantities of oligomers of di(isopropenyl)benzene, with low conversions and low molecular weights.
Guan (U.S. Pat. No. 5,767,211 (1998)) has described the synthesis of non-crosslinked, multi-functional, hyperbranched polymers by free radical polymerization of di- or tri-vinyl monomers in the presence of a chain transfer catalyst. The process disclosed herein produces polymers that are substantially linear with few or no points of branching on the polymer backbone.
Issued U.S. Pat. No. 7,022,792, the disclosures of which are hereby incorporated herein by reference in their entirety, discloses the use of hydrogen gas or hydrogen atom donors for the initiation of polymerization of unsaturated monomers in the presence of cobalt chain transfer catalysts.